The principal overall objectives are to elucidate the ecology of the dengue viruses and related arboviruses in Malaysia, with special reference to the jungle cycles; and to establish the importance of dengue as a zoonosis involving primates. Continuing and modified field studies and laboratory transmission experiments are to be conducted in an effort to confirm the importance of the Aedes (Finlaya) neves subgroup of mosquitoes as the important jungle canopy vectors. A continuing effort will be made to gather additional evidence linking dengue virus activity in jungle, rural, and town habitats and to assess the true roles of the known vectors in relation to disease in man. A variety of tested, collecting methods will be employed. Laboratory studies include isolation, characterization, and identification of viruses utilizing mice, cell cultures, and parenteral inoculation of mosquitoes, and detailed serology using microtiter techniques and plaque-reduction neutralization tests.